Problems running sos-commands

Yesterday I tried opening up a standard dump file from a 64-bit Windows 2008 Server. It opened up just fine in windbg, but when I tried executing a command I got the following:0:000> !dumpheap -stat The garbage collector data structures are not in a valid state for traversal.It is either in the "plan phase," where objects are being moved around, orwe are at the initialization or shutdown of the